Portable computing devices are increasingly subject to the two opposing requirements of greater portability through smaller size and weight, and greater utility through more and greater capabilities. In response, manufacturers of portable computing devices continue to employ ever newer battery technologies and continuing improvements thereto in an effort to provide ever greater amounts of electric power in an ever smaller physical configuration for these portable computing devices.
However, despite great strides in battery technology, even the best of current day batteries have limits, and not just in capacity. For example, despite the relatively high charge densities of current lithium-ion and lithium-polymer batteries, there are limits on the rate of current output of such current day batteries that result from internal resistances, temperature increases, and battery health more generally. This becomes significant as more power-consumptive features such as amplified audio output, long-range radio frequency wireless communications, and flash lighting for the taking of pictures become increasingly commonplace in portable computing devices.
Such limitations on battery current output combined with the use of such power-consumptive features can result in dips in the voltage level of the electric power output of such batteries that can lead to unstable operation of portable computing devices. This can become particularly acute as such batteries become depleted such that they can no longer sustain supplying electric power at any relatively high current level without the voltage level of their outputs dropping to levels that may violate minimum system operating requirements. This can also become particularly acute for even a fully charged battery when multiple ones of such power consumptive features are used simultaneously.
Typical portable computing devices attempt to continue to support high rates of current output of such batteries, even as they become progressively more depleted, through the use of boost power converters and/or high density capacitors to absorb short periods of particularly high power consumption. Unfortunately, such measures are often insufficient as more and more of such power-consumptive features are increasingly incorporated into portable computing devices, especially where those power-consumptive features make use of higher amounts of electric current for periods of time that are longer than can be accommodated through the use of such measures.